I think Kusuo Saiki and Anzu Hoshino would be good friends. Two people who don't want to be apart of a harem but still become friends with them and treat them like people. Both love sweets (Saiki would feel sad that this tiny seemly-indestructable magical wizard is preventing her from eating her favorite sweet. He would have killed Riri). Neither can handle bugs. Both have stereotype friends that actually have more to them than they seem (they would love each other's friend groups. For the most part anyway). Saiki would feel safe around Anzu since she would NOT let anyone get away with stalking or trying to trap him. Saiki wouldn't let anyone do the same to her either. I think after a situation got a bit too out of hand in Anzu's life, Saiki would tell her he has psychic powers and she would be like "Are you with the wizard?" and he'd be like "No" and then they'd be friends.
anyways i watched all of romantic killer recently and i'm now actively fighting off the urge to make either an enstars au inspired by it or write a stupid longfic that expands off where s1 ends . also the keito, hiiro, and hiyori VAs are the main three love interest guys,